In my limited searching, the Specialized Transition brakes are available only on the Specialized frames, not as aftermarket parts. If you really really really want some, I would suggest you

a.) mug Paolo Bettini next time you see him time trialling. He's pretty small, you can take him.

b.) buy a transition frame module (3k USD), remove the brakes, and sell the frame on ebay, likely at a loss.

Neither option seems particularly palatable to me.